Existing networks (e.g., 2G, 3G, 4G, WLAN etc., and evolution thereof) and future Radio Access and Core Networks (5G, 6G, etc.) require solutions for supporting optimized network functionality for addressing new use cases for cellular technologies.
Evolved Packet System (EPS) is the Evolved 3GPP Packet Switched Domain and consists of Evolved Packet Core (EPC) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN). EPS also supports packet switched access over GSM/EDGE Radio Access (GERA), Universal Terrestrial Radio Access (UTRA) and Wireless Local Area Network (WLAN).
FIG. 1 illustrates an example EPC architecture for 3GPP accesses (GERAN, UTRAN and E-UTRAN), which includes, for example, a PGW (PDN Gateway), SGW (Serving Gateway), PCRF (Policy and Charging Rules Function), MME (Mobility Management Entity), HSS (Home Subscriber Service) and user equipment (UE). The LTE radio access, E-UTRAN, consists of one more eNBs. FIG. 1 illustrates the architecture for 3GPP accesses. In these types of accesses, the radio interface is specified by 3GPP (e.g., E-UTRA).
FIG. 2 illustrates an example E-UTRAN architecture. The E-UTRAN consists of eNBs, providing the E-UTRA user plane (PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towards the UE. The eNBs are interconnected with each other by means of the X2 interface. The eNBs are also connected by means of the S1 interface to the EPC (Evolved Packet Core), more specifically to the MME (Mobility Management Entity) by means of the S1-MME interface and to the Serving Gateway (SGW) by means of the S1-U interface.
FIG. 3 illustrates an example EPC architecture that also takes into account non-3GPP accesses. In non-3GPP accesses, the radio interface is not specified by 3GPP (e.g., WLAN). A non-3GPP access may be treated as trusted or untrusted. Whether a non-3GPP access should be treated as trusted or untrusted depends on, for example, security considerations and operator policies. In this regard, a trusted access may be managed by an operator (e.g., an operator hotspot) whereas, an untrusted access is not managed by the operator (e.g., a Wi-Fi access point at home). In a non-3GPP access, a security gateway (ePDG) is used between the non-3GPP domain and the operator's network. The UE sets up a secure tunnel to the ePDG, where there is a S2b interface between ePDG and PGW. A trusted 3GPP access hosts a gateway in the non-3GPP domain. For WLAN, the gateway is denoted Trusted WLAN Gateway (TWAG), where there is a S2a interface between TWAG and PGW.
Future networks are expected to support new use cases going beyond the basic support for voice services and mobile broadband (MBB) currently supported by existing cellular networks (e.g., 2G/3G/4G). An example new use case includes evolution of MBB including evolved communication services, cloud services, and extended mobility and coverage. Another example new use case includes mission critical machine type communication including intelligent traffic systems, smart grid, and industrial applications. Another example new use case includes massive machine type communication including sensors/actuators and capillary networks. Another example new use case includes media including efficient on-demand media delivery, media awareness, and efficient support for broadcast services.
These use cases are expected to have different performance requirements (e.g., bit-rates, latencies, mobility, availability, etc.) as well as other network requirements affecting the network architecture and protocols. Supporting these new use cases may require that new players and business relations are needed compared to existing cellular technologies. For example, it is expected that future networks should address the needs of enterprise services, governments services (e.g., national safety, verticals industries (e.g., industry automation, transportation), and residential users. These different users and services are also expected to place new requirements on the network.
Accordingly, it is expected that new services with a wide range of heterogeneous requirements need to be supported. There is a need to be able to support these new services in a cost efficient way using common network infrastructure (e.g., radio, transport, networking, processing, and storage) and functional components (e.g., mobility manager) applied to specific business segments (e.g., verticals with specific requirements), while still making it possible to optimize the network when it comes to deployment, functionality needed, scalability, etc. for these new services. Additionally, it is desired by one of ordinary skill in the art to provide isolation between the different business segments of the common network infrastructure to prevent one user associated with one or more services from causing problems to other users and services.
In some 3GPP solutions, an operator may deploy one (or more) dedicated core networks (DECOR) (also referred to as “network partitions” or “slices”) within a PLMN with each core network dedicated for a specific type(s) of subscriber or device. The DECOR solution enables an SGSN or MME initially handling a UE to redirect a UE to a specific dedicated core network (e.g., a different SGSN or MME) based on subscription information and operator configuration, without requiring the UEs to be modified. A limitation of this 3GPP solution is that it only works when the UE connects via a 3GPP access, and no support is available in case the UE connects via WLAN integrated to EPC using S2a/S2b interfaces.
A particular problem not addressed by the existing solutions for network partitioning or slicing is how to ensure that the selected network partition is preserved as the UE moves between 3GPP access (e.g., LTE) and WLAN access. One particular problem in this case is that the network partition selection mechanism may differ between access types. For example, when selecting a dedicated core network (e.g., network partition) based on DECOR, the MME/SGSN may take into account information that is only available in 3GPP access and that is not available in WLAN access (e.g., UE CATEGORY and Low Access Priority Indicator). When network partition selection is instead based on extra information in the signaling from the UE to the network (e.g., in case the UE provides some kind of network partition type or identity), there may still be multiple instances of a single network partition type and a partition selection function in the network may direct the UE to one particular partition instance. This may result in the network partition (instance) selected in 3GPP access differing from the network partition (instance) selected in another access such as WLAN.
Thus, there is no guarantee that the network partition selection in 3GPP access and WLAN access always gives the same result. This is particularly a problem when handover between 3GPP and WLAN access is supported were the UE would need to be served by the same network partition (instance) in both accesses.